Skip to main content

Estrogen replacement in ovariectomized rats results in physiologically significant levels of circulating progesterone, and co-administration of progesterone markedly reduces the circulating estrogen

Endocrine volume 6, pages 125–131 (1997)Cite this article

Abstract

Estrogen or progesterone replacement in ovariectomized rats is an often-used experimental system for determination of the specific effects of these hormones. In this study, two different delivery systems and two different dosage levels of estrogen, progesterone or a combination of the two have been used. Estrogen and progesterone in the circulation have been measured in response to each treatment. It is reported that estrogen treatment (237.2±49.2 pg/mL) results in physiologically significant levels of circulating progesterone (11.1±1.3 ng/mL). Also, co-administration of progesterone (23.7±2.0 ng/mL) with estrogen decreases the level of estrogen over that seen with estrogen alone (96.7±19.2 pg/mL with progesterone vs 237.2±49.2 pg/mL without progesterone). Thus, contrary to expectations, estrogen replacement therapy is not specific to estrogen and some of the antagonistic effects of progesterone are the result of a decrease in circulating estrogen, and not a specific effect on a target tissue. Whereas the mechanism of these effects has not been determined, obvious artifactitious phenomena have been excluded as being their cause. These results could have a major impact on the interpretation of past and future experiments of this kind.

This is a preview of subscription content, access via your institution.

Access options

Buy single article

Instant access to the full article PDF.

43,34 €

Price includes VAT (Finland)
Tax calculation will be finalised during checkout.

References

  1. Kitay, J. I. (1961).Nature 192, 358,359.

    PubMed  Article  CAS  Google Scholar 

  2. Kitay, J. I. (1961).Endocrinology 68, 818–824.

    PubMed  CAS  Google Scholar 

  3. Kitay, J. I. (1965).Endocrinology 77, 1048–1052.

    PubMed  CAS  Google Scholar 

  4. Kitay, J. I. (1965).Proc. Soc. Exp. Biol. Med. 120, 193–196.

    PubMed  CAS  Google Scholar 

  5. Kime, D. E., Vinson, G. P., Major, P. W., and Kilpatrick, R. (1980). InGeneral, Comparative and Clinical Endocrinology of the Adrenal Cortex, vol. 3. Jones, C. I. and Henderson, I. W. (eds.). Academic, pp. 183–264.

  6. Ruhmann-Wennhold, A., Johnson, L. R., and Nelson, D. H. (1970).Biochim. Biophys. Acta 223, 206–209.

    PubMed  Article  CAS  Google Scholar 

  7. Nowak, K. W., Neri, G., Nussdorfer, G. G., and Malendowicz, L. K. (1995)Life Sci. 57, 833–837.

    PubMed  Article  CAS  Google Scholar 

  8. Fajer, A. B., Holzbauer, M., and Newport, H. M. (1971).J. Physiol. 214, 115–126.

    PubMed  CAS  Google Scholar 

  9. Feder, H. H., Brown-Grant, K., and Corker, C. S. (1971).J. Endocrinol. 50, 29–39.

    PubMed  CAS  Article  Google Scholar 

  10. Piva, F., Gagliano, P., Motta, M., and Martini, L. (1973).Endocrinology 93, 1178–1184.

    PubMed  CAS  Article  Google Scholar 

  11. Resko, J. A. (1969).Science 164, 70,71.

    PubMed  Article  CAS  Google Scholar 

  12. Feder, H. H. and Ruf, K. B. (1969).Endocrinology 84, 171–174.

    PubMed  CAS  Article  Google Scholar 

  13. Tapper, C. M. and Brown-Grant, K. (1975).J. Endocrinol. 64, 215–227.

    PubMed  CAS  Google Scholar 

  14. Slikker, W., Jr., Lipe, G. W., Sziszak, T. J., and Bailey, J. R. (1984).Drug Metab. Distribution 12, 148–153.

    CAS  Google Scholar 

  15. Lye, S. J., Nicholson, B. J., Mascarenhas, M., MacKenzie, L., and Petrocelli, T. (1993).Endocrinology 132, 2380–2386.

    PubMed  Article  CAS  Google Scholar 

Download references

Author information

Affiliations

  1. Division of Biomedical Sciences, University of California, 92521-0121, Riverside, CA

    Jo-Wen Liu, Denise D. Dawson, Christine E. Peters, Mary Ann Baker & Ameae M. Walker

Authors
  1. Jo-Wen Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Denise D. Dawson
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Christine E. Peters
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Mary Ann Baker
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Ameae M. Walker
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Ameae M. Walker.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Liu, JW., Dawson, D.D., Peters, C.E. et al. Estrogen replacement in ovariectomized rats results in physiologically significant levels of circulating progesterone, and co-administration of progesterone markedly reduces the circulating estrogen. Endocr 6, 125–131 (1997). https://doi.org/10.1007/BF02738955

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02738955

Key Words

  • Estrogen
  • progesterone
  • ovariectomy
  • rat serum
  • combined therapy